The few times I have tried to do intensive resistance training, above 60% of my PR, I have started feeling weak after the second or third day. I don't use caffe

The few times I have tried to do intensive resistance training, above 60% of my PR, I have started feeling weak after the second or third day. I don't use caffeine for pre-workout. This might not be common, but I personally experienced a significant increase in exercise induced syncope and near-syncope when fasted. I also imagined that muscle recovery would be less efficient or take longer from a fasted state. I have hit rowing/ERG goals and made time improvements so I feel comfortable saying that fasting doesn't hinder my cardio. I understand that energy goals are correlated with body size, we were discussing a general minimum kcal threshold for unsupervised dieting. I am unsure why you feel estimated BMR/RMR - 200 kcal is unscientific. I was told that without supervision, it would be hard to ensure proper nutrition on a very low calorie diet. Additionally, he expected that some people would fall into a binge-restrict cycle because they can't sustain their usual energy level. I was additionally curious because there have been days I forget to eat, and thinking back I realized my total calories for those 24 hours totaled less than 600 kcal.